For years I have heard the statements about selected members of the Mormon Church being asked to walk back to Missouri. I have been unable to find the source for these statements. Is there in fact a reliable source for this belief or is this a Mormon urban legend?
What you refer to in your question is not a Mormon urban legend. It may not even qualify for a Camas, Washington local legend. You state that you had heard those reports for years. My question to you is, were they all from the same person? Although the time will come when enough members of the Mormon Church will be living in Missouri to warrant the construction of the grand temple that will be built in Jackson County, the Mormon Church today is encouraging its members to live and build up Zion in their local areas. However, a return of the members of the Church to Missouri has been prophesied from the time that the Latter-day Saints were expelled from that country. In the 1877 general conference of the Mormon Church Elder Lorenzo Snow, just a year before he was called to be the Church President, made the following statement:
“As knowledge and efficiency are obtained gradually, we may expect that the experience that we are getting now in learning how to build up cities in our present condition, conforming as near as possible to the holy order of God, is in order to prepare us by and by to return to Missouri, whence we were driven, and there build up cities and temples to the name of the Most High, upon which His glory will descend” (5 April 1877, JD, 18:374).
Elder Gerald N. Lund has quoted Brigham Young as prophesying the conditions under which the Saints would be returning to Missouri, as follows:
“There seems to be another reason why the saints will not have to redeem the land of Zion by actual combat and warfare. It must be remembered that the United States will see great chaos and destruction in the form of mobs and anarchy. It is not clear from the prophecies just exactly when the return to Missouri will take place in relationship to this time of civil destruction, but Heber C. Kimball spoke of a prophecy made by President Brigham Young in which he said that upon the return of the saints there would be no inhabitants in that area of Missouri to plague the Church” (Gerald N. Lund, The Coming of the Lord , p.110).